Thermoplastic nylon compositions toughened by the addition of metal ion neutralized acid containing acrylic copolymer rubber particles having a size in the range of 0.01 to 1 microns are known, U.S. Pat. No. 4,174,358. These tough compositions are useful for molded parts where high impact resistance is important, but they are not satisfactory for applications where elastomeric properties, for example, good compression set or tension sets, are needed.
Metal ion neutralized acid containing acrylic copolymer rubbers are thermoplastic elastomeric materials useful for molded parts exhibiting excellent compression set and tension set but they are not satisfactory for applications where high strength or good oil resistance are needed or, where high temperatures are encountered.